| dc.description.abstract | Outdoor air pollution is a broad and complicated issue that poses a real threat to human health and the environment. Past research demonstrates a link between urban air pollution and increased rates of mortality and morbidity (Vigotti et al, 1996; Ostro et al, 2000; Metzger et al, 2004; Curtis et al, 2006; Bell et al, 2008; Stieb et al, 2002). It has also shown to be detrimental to the environment (United States Environmental Protection Agency (EPA), 2008a; Health Canada, 2003, Health Canada, 2006b). Such findings have only continued to strengthen the concern that outdoor air pollution continues to pose a threat to public health (Samet et al, 2000). As this area of research continues to receive ongoing attention it also proves to be a difficult area to study. What makes researching outdoor air pollution so complicated and broad is that air pollution is a heterogeneous mixture of gaseous and particulate components that vary through the seasons, diurnally and spatially (Davidson et al, 2005; Bell et al, 2008, Gibson et al, 2009) Additionally, since the industrial revolution, the air pollutant mix has changed and so have their sources (but not uniformly on a global scale, e.g. developed versus developing world). Pollutants that received a large amount of attention for their impact on the environment include sulphur dioxide (SO2) and oxides of nitrogen (NOx) both of which led to the formation of acid deposition (Health Canada, 2003, 2006b) and carbon dioxide (CO2), which is a greenhouse gas (Health Canada, 2006b). Air pollutants of health concern include ground-level ozone (O3), carbon monoxide (CO), oxides of sulphur (SOX) - a mixture of SO3 & SO2 , nitrogen oxides (NOX) volatile organic compounds (VOCs), and Particulate Matter (PM) - PM2.5 & PM10 (the subscript indicates what aerodynamic diameter is in consideration). PM2.5 indicates those particles that are 2.5 microns and smaller where as, PM10 indicates aerodynamic diameter 10 microns and below; this classification is split into two fractions; coarse particles (PM2.5-10) and fine particles (PM2.) (EPA, 2008a; Health Canada, 2006b). Research over the last decade has shown that ambient concentrations of these pollutants are declining in Canada (Curtis et al, 2006). This is due to tighter emissions regulations and the retro fitting of scrubbers on power stations in the NE USA, which have been particularly effective at reducing NOx and O3 seen in Eastern Canada (Kim et al, 2006). However, in recent years some pollutants, especially PM, are being exacerbated by our increased use of vehicles and industrial chemicals (Curtis et al, 2006). | en_US |
